[EM] Realistic strategy questions
Toby Pereira
tdp201b at yahoo.co.uk
Mon Feb 24 10:21:52 PST 2014
Can I ask which voting systems will be included in this? Among other things
I'd like to see how different Condorcet methods compare with each other and
also margins v winning votes. Certainly something to look forward to,
although I have nothing useful to add about the strategy types at the
moment.
On Monday, 24 February 2014 17:46:39 UTC, Jameson Quinn wrote:
> I have been working on my program for measuring the Voter Satisfaction
> Efficiency (formerly known as BR) of various systems. It's just about ready
> to do a big run, but before I do that, I'd like to get as many of the
> activists here to say what they think are reasonable settings for
> generating scenarios. In particular, I have to decide proportions for
> various kinds of strategic voters.
>
> Here's a few possible kinds of voters:
>
> 1. Honest: Will always map their utility onto a vote as honestly
> (linearly) as possible, after normalization over the range of candidates
> available.
> 2. Media-based Honest: As above, but when normalizing, they will
> ignore all candidates who are worse than both polled frontrunners.
> 3. Fully strategic: Will always strategize by maximizing the ballot
> distance between the two (honestly) polled frontrunners.
> 4. Weakly strategic: Will strategize, but only as much as "necessary".
> That is, assuming no other voters strategize, they will shift their vote,
> focusing on the margin between the polled winner and runner-up. In a
> Condorcet system, such a voter would always be honest. In a median system,
> they would exaggerate to ensure they graded the winner and runner up on
> opposite sides of both of their polled total grades, but not necessarily to
> an extreme; so if their honest vote was A,B,C,D,F and the polled grades
> were D,C+,C-,D,D, then they'd vote A,B,D,D,F.
> 5. Lazily strategic: Fully strategic if and only if their weakly
> strategic vote would not be identical to their honest vote.
> 6. Threshold strategic: Fully strategic if and only if their utility
> (satisfaction) difference between the polled frontrunners is greater than
> some threshold (in absolute value)
> 7. One-sided strategic: Will strategize if and only if they prefer the
> polled runner-up to the polled winner.
> 8. 20/20 hindsight: Fully strategic if and only if one of the last N
> election results was changed by strategy. (When simulating, you'd just use
> some constant probability for each election system, and find an equilibrium
> point for that probability).
> 9. Sheep: strategic iff more than X% of the non-sheep voters are.
> 10. Cliquish: Certain probability of being each of the above kinds,
> except with a certain extra probability of being the same as other voters
> who share similar utilities.
>
> Obviously, it would be easy to extend the above list by combining the
> various aspects there.
>
> Personally, I find ALL of the above strategic types to be essentially
> plausible. I know that the full decision rule for some (such as weakly and
> lazily) are more complex than the explicit thought processes of 99.99% of
> voters, but in practice I think it would be easy to end up acting like that
> through implicit and/or subconscious heuristics. Thus, in particular, I
> find it extremely IMplausible that the electorate would consist only of
> types 1 and 3, as previous BR simulations generally assumed.
>
> The question, then, is: how many of each kind of voter should I put in? Of
> course, I'll run several scenarios, but there's no way I can fully explore
> the 8-simplex of possible combinations of the above 9 voter types. So I
> have to choose where to focus my attention.
>
> And furthermore, I think it's valuable to say which percentages you find
> plausible before you learn how your favorite voting system does under those
> percentages. In my debugging so far, I've gotten a glimpse of the impact of
> types 1, 3, 4, 5, and 7 above; but I have not looked at the rest at all. So
> here's a scenario I find reasonable, and which I really don't know how it
> will turn out for my currently-favorite systems:
>
> Each voter has a "honesty type" which are 50% honest and 50% media-based;
> a "strategy type" which are 75% full and 25% weak; and a "decision type"
> which are 30% hindsight (N=1-3), 30% threshold (X=0.5-2 SD), 20% lazy, 10%
> one-sided, 5% always-honest, and 5% always-strategic. They use their
> "decision type" to decide whether to vote according to their "honest type"
> or their "strategic type". Cliquishness is around 70% (note that even at
> that high level, there are good chances of a scenario where the
> cliquishness does not lead to one-sidedness).
>
> What do others think is a reasonable scenario? I'd particularly like to
> hear from Clay. Clay, I know we're likely to disagree over the meaning of
> my VSE numbers once I have them ready; and, only human, we'll probably both
> tend to rationalize to make our points. I think that it will help
> ameliorate that disagreement if we undercut those future rationalizations
> by each precommitting to take our own chosen set of numbers seriously, even
> if those are two separate sets of numbers.
>
> Jameson
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20140224/8773f144/attachment-0004.htm>
More information about the Election-Methods
mailing list